According to the Porter's Handbook (5.12.2.3.) default options must be added to
OPTIONS_DEFINE. This policy has been implemented only recently that's why we
have many ports violating this policy.
This patch adds the default options specified in the Porter's Handbook to
OPTIONS_DEFINE where they are being used. Ports maintained by
gnome@FreeBSD.org, kde@FreeBSD.org and x11@FreeBSD.org have been excluded.
Approved by: portmgr (bapt)

The author has not found any simple programs that listen on a device and
run commands based on the values received.
keyboard-daemon binds to a device (for example, a remote control) and
listens for button presses. These are then mapped to programs that are
executed.
WWW: http://www.bayofrum.net/cgi-bin/fossil/keyboard-daemon/